i tried adjusting the resistor higher to 470k still shows 99

For TTL, you should use a longer time constant. For a cleaner reset, you should use a Schmitt Trigger gate which will tolerate a "slowly" rising input more predictably.

You need to work on your schematic drawing skills.

 

Which simulator are you using.?

Multisim

 

Thanks Dennis.
It works just fine in LTS, are you familiar with Multisim.?
Initially the TS circuit had no Power On Pload pulse, a very basic Pload circuit has been added.

E

 

For TTL, you should use a longer time constant. For a cleaner reset, you should use a Schmitt Trigger gate which will tolerate a "slowly" rising input more predictably.

You need to work on your schematic drawing skills.

sorry im just new to this things
what is a schmitt trigger gate? where do i use it?

 

Is the TS starting the transient simulation from zero volts or are they allowing the DC operating point to be calculated first?

 

i got it to work by connecting the load to the vcc and ground with 2 resistors
do you guys think this would also work in actual?
is multisim accurate with its simulations?

 

is multisim accurate with its simulations?

Multisim is not 100% accurate; no simulator is; that's why you always build the circuit to prove that the simulation was accurate enough.

I know for a fact that Multisim makes inaccurate assumptions regarding the current required to turn on an LED. It forced me to use smaller resistors than necessary, or would actually be used in a circuit.

 

are you familiar with Multisim.?

I stopped using Multisim in the early stages of learning how to use it. I found it to not be very realistic for anything that wasn't digital. I was using the free version (Multisim Blue) which was very limited in the number of usable components available.

 

Requiring a 1k resistive divider in the Pload line does not make any sense.
I suspect there is a problem with the simulation.
Why don't you just build the Units decade without the 74LS47 and the decoding.
Prove that part and then add the remainder of the circuit.
E

 

what is a schmitt trigger gate? where do i use it?

A Schmitt Trigger has hysteresis that allows it to give clean transitions on slowly changing inputs. On normal inputs, the output can toggle when the input voltage is between the limits for LOW and HIGH. Hysteresis addresses that issue.

SN7414 is a hex inverting schmitt trigger.

 

thanks for the help guys i will just test this in actual see if it will work i wont be simulating the circuit again though cause it seems to be buggy so there's no point. ill update if it works or theres a problem
any suggestion for a better simulator?

 

hi b,
I use the free LTSpice simulator.
http://www.analog.com/en/design-cen...MYYU2aTRCrA3LIx-3-eOskZ9WQUTP3AYaAtVmEALw_wcB
E
Also join the user group.
https://groups.yahoo.com/neo/groups/LTspice/files

 

Does multisim has a way to generate a Hi-Lo-Hi pulse. In proteus, it is very hard to generate a power-start-up pulse using RC circuit. I normally do it this way.

(hope I didnt spoil the soup...)